This invention relates to mass transfer devices of the type which include a semipermeable membrane; and more particularly, to dialyzers of the type used in artificial kidney systems.
Artificial kidney systems are used to treat a patient's blood so as to remove waste products therefrom. One type of dialyzer used in such systems is commonly referred to as a coil dialyzer. It includes a flattened, tubularly-shaped, semipermeable membrane of a material, such as cellophane or polycarbonate, which along with an appropriate support member, is wound or coiled about a center core and enclosed in a cylindrical housing. Blood from a patient enters the dialyzer through an inlet in the core, flows through the dialyzer inside the membrane and exits the dialyzer through an outlet. Dialysis solution flows in a crosswise direction through the housing and between the wound support and membrane.
The dialysis solution contacts the membrane, and due to the difference in waste product concentration between the blood and the dialysis solution, the waste products, such as urea and creatinine, diffuse from the blood through the membrane and into the dialysis solution.
During treatment of blood in a dialyzer, water is removed from the blood by virtue of a process known as ultrafiltration. The amount of water which is removed is related to the difference in blood pressure and dialysis solution pressure on opposite sides of the membrane. Existing dialyzers operate at relatively high blood pressure levels which is related to the size and shape of the membrane and the membrane support. This high pressure may result in undesirably high and/or variable levels of water removal.
It is an object of this invention to provide a dialyzer wherein water removal is controllably maintained at a low level.
In existing dialyzers the conduits which carry blood to and from the dialyzer may become kinked where they enter and exit the dialyzer. Further, in existing constructions dialysis solution exits from the top of the dialyzer. This results in an esthetically displeasing "sloshing" sound.
It is another object of this invention to provide a dialyzer structure wherein kinking of the blood conduits is minimized and "sloshing" eliminated.
The cellophane membrane is relatively fragile and may rupture or tear during assembly of the dialyzer when the membrane is sealed and is connected to the blood conduits. It is yet another object of this invention to provide an improved end seal and connector which minimizes membrane damage.
Furthermore, existing dialyzers are relatively expensive to manufacture, and it is therefore another object of this invention to provide a dialyzer which is less expensive to manufacture.
These and other objects of this invention will become apparent from the following description and appended claims.